Keyed insulating board



April 21, 1925. Y 1,534,142

C. A. ROLFE KEYED INSULATING BOARD Filed Aug. 1'7, 1921 f1 l 6 .2512 f//lllIllIllll/A-fll/lll///n'llIll/[l//l/Z W Patented Apr. 211, 1925.

Yuiursn STATES `PA'l-"ENT OFFICE.,

CHAILES A. ROLFE, OF ST. PAUL, MINNESOTA.

xEYnn INsULATiNe BOARD.

Another object is to provide a face and' back in a keyed insulatingboard .wherein the face, which has the keys therein, will be of a firmer texture and hence of greater strength than the back, Awhich will be of a looser texture and having higher insulating qualities than thefront.. n

Another object is to pro 'de improved i 2Q means for fastening the face and'back together. e v Y In the drawing'Fig. l is a side elevation of the face portion of a board embodying my invention; Fig. 2 is a section .taken on the line 2 2, Fig. l; Fig. 3 is a section taken on the line 3 3, Fig. 1 and Fig. 4 is afperspective view of the complete board. YThe face 1, Figs. 1, 2 andl 3 is made of compressed pulp and is preferably of a 30. quite hard nature, its density being comparatively high so it will have a high breaking strength. t

Keys 2 are formed therein preferably by a gang milling cutter operated on the back face of the board.

The cutter is of such shape as to form a a dovetail slot asclearly shown at 3, Fig. 2, and as the cutter is fed down into the board fro-m the back the ends. of the cutter are 0 formed as at 4, Fig. 3 so the lock formed for the plaster by this cutter is substantially bevelled on all four sides.4

The bank face 5 ofythis board maybe coated with a mastic compound so it will firmly adhere @o the back board c, Fig. 4.

This back board is preferably of a looser texture than the face board and hence will have a higher; insulating quality; one face of this' board may also be coated with a mastic compound so the` two may be joined together by` means ofthe masticcoating on A y 1. In an insulating board the combination thetwo boards as shown in Figf4.

. f Application led August 17, 1921. A'Serial No. 493,154.

The face bo-ard may be superimposed on y the back board as shown in Fig. 4 so that when a number of such boards are mounted on studding'the joints' may be bro-ken on the studding and also on the topfr and bottom of the boards.

In addition to the union effected bythe mastic coating the two boards may be stitched .together by wire staples or any .suit` able form of stitching as indicated aat 7,`y

Fig. 4. i s While thev 'board may be made of any .suitable area and thickness, Iprefer to make it four foot square, which will take four studdings Set on sixteen inch centers and have the rows of `stitching sixteen inch/es part so as to be intermediate of the studlng.

Such a board when properly .placed on the studding makes it stiffer thana sheath because the face of the board is strong and rigid, yetm it provides a practically perfect insulation as the back may be of a material having very high insulating qualities.

By staggering' the keys as shown in Fig.- i

l the strength of the board is not imp-aired as it would be if the keys ran longitudinally straightacross the .face of the board, yetthe hold on the plaster is stronger than such al construction would give and furthermore because the face board is hard and has a lfirm surface the suction on the plaster is much greater than would be the case whe-re the plaster is put directly on a board having high insulating qualities.

In manufacturing the face boa-rd can be i While I have described my invention and l illustrated it in one particular design, I do" not wish it understood that I limit myself to this construction, as it is evident that the application of the invention may be varied in many'ways within the scope of the foll' lowing claims.

Claims: i

of a face board of lfirm texture and considnation of a face board of a firm texture of v10 erable thickness having a definite mechaniconsiderable thickness having plaster keycal stren h and a backboard 'of loose texing means and a back board of considerable ture an considerable thickness joined thickness formed with loose texture and of -5 thereto having lesser strength but having high insulating qualities joined thereto, said high insulating properties, the two boards boards being of comparatively the same 15 forming the completed composite board bethickness. l ing of comparatively equal thickness.

2. In a keyed insulating board theI combi- CHARLES A. ROLFE. 

